The Slieve Bloom mountains which are formed of red sandstone, slate and shale are located along the border with Offaly. Its highest peak, Arderin, rises to 528 metres (1732 Ft) above sea level.

The river Barrow rises here and flows along the eastern boundary of the county.The remainder of the county is mainly undulating lowlands underlain by limestone. In areas which are not well drained there are extensive peat bogs.

The Bog of Allen which has an area of about 970 square kilometers lies in the central plain of Ireland. It stretches from county Kildare through parts of Laois, Offaly, and Westmeath. In 1950 Ireland's first peat burning electricity generating station opened at Portarlington to take advantage of this abundant cheap local energy source.

The railway from Dublin to Cork and Limerick passes through Laois, with branches from Portarlington to Athlone and from Ballybrophy to Nenagh. From Port Laois the N8 road to Cork joins the N7 from Dublin to Limerick. Portlaoise also lies on the N80 road from Athlone to Wexford

About a quarter of the population of Laois work in agriculture. Most of the land that is not peat bog or upland is utilised for farming. About 20% of it grows crops such as barley, potatoes, sugar beet, turnips, and wheat. The remainder is grassland and is used mainly for beef cattle There is also dairy farming and pig production, and sheep are raised mainly on the upland areas.

The service sector employs the largest percentage of the population, with nearly 50% being employed in retail and wholesale distribution, catering, education, health, public administration, and transport. About 16% work in manufacturing such as food processing and general engineering.

Laois and Offaly send five Td's to the Dail Eireann, A county council, based in Port Laois, is in charge of local government. The Republic of Ireland's top security prison is also located there.

Read about County Laois from Samuel Lewis' Topographical Directory of Ireland 1837